1. Field of the Disclosure
The present disclosure relates generally to image forming devices, and, more particularly, to positional control features of two replaceable units for an electrophotographic image forming device.
2. Description of the Related Art
In order to reduce the premature replacement of components traditionally housed within a toner cartridge for an image forming device, toner cartridge manufacturers have begun to separate components having a longer life from those having a shorter life into separate replaceable units. Relatively longer life components are positioned in a first replaceable unit, such as an photoconductor unit (PC unit), while shorter life components are positioned in a second replaceable unit, such as a developer unit, that matingly engages with the first replaceable unit. The combination of the two replaceable units form what is termed as an imaging unit.
The toner supply for the image forming device, which is consumed relatively quickly in comparison with the components housed in the imaging unit, is provided in a reservoir that periodically feeds toner to the developer unit of the imaging unit. In this configuration, the number of components housed in the toner cartridge unit is reduced in comparison with traditional toner cartridges.
It is important that the developer unit be precisely aligned within the PC unit when combining to form the imaging unit. If the developer unit is misaligned with respect to the PC unit, the developer roll providing toner to the PC drum may be skewed leading to uneven toner transfer to the PC drum. Additionally, if the imaging unit is misaligned with respect to the media path or the laser beam, skewing of the latent image on the PC drum or the printed image may occur. These misalignments potentially may result in mechanical and print quality defects. Further, if the developer unit is misaligned, a drive gear on the developer unit may not achieve proper gear mesh with a corresponding drive gear in the PC unit potentially resulting in gear cogging. The same potential problems may occur between the engagement of the imaging unit with the drive sources provided in the imaging device. The developer unit and imaging unit must also be rigidly held in place after it is installed in the image forming device in order to prevent the positional alignment of the develop unit and the PC unit from being disturbed during operation. The requirement for accurate positional control must be balanced with the need to permit a user to easily load and unload the developer unit into and out of the imaging unit and/or the imaging unit into and out of the image forming device. Accordingly, it will be appreciated that precise alignment of the developer unit and the imaging unit and relatively simple insertion and removal of the developer unit into and out of the imaging unit and the insertion and removal of the imaging unit into and out of the image forming device is desired. Also desired would be the ability to compensate for skew between rotational axes of the PC drum in the PC unit and the developer roll in the developer unit caused by tolerance stack up due to part-to-part variations.